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To determine whether feeding a sustainable, algal source of docosahexaenoic acid (DHA) to sheep during late pregnancy would improve neonatal lamb vigour, 48 English mule ewes, of known conception date, were divided into four treatment groups. For the last 9 weeks of gestation, ewes received one of two dietary supplements: either a DHA-rich algal biomass providing 12 g DHA/ewe per day, or a control supplement based on vegetable oil. The four dietary treatment groups (n = 12) were: control supplement for the duration of the trial (C), DHA supplement from 9 to 6 weeks before parturition (3 week), DHA supplement from 9 to 3 weeks before parturition (6 week) and DHA supplement for the duration of the trial (9 week). Dietary supplements were fed alongside grass silage and commercial concentrate. There was a tendency for gestation length to be extended with increased duration of DHA supplementation (P = 0.08). After parturition, the concentrations of eicosapentaenoic acid (EPA) and DHA in ewe and lamb plasma and colostrum were elevated in line with increased periods of DHA supplementation. Lambs from the 6-week and 9-week groups stood significantly sooner after birth than lambs from the C group (P < 0.05). These data show that neonatal vigour may be improved by the supplementation of maternal diets with DHA-rich algal biomass and that this beneficial effect depends upon the timing and/or duration of DHA allocation.
Unsatisfactory reproductive performance in dairy cows, such as reduced conception rates, in addition to an increased incidence of early embryonic mortality, is reported worldwide and has been associated with a period of negative energy balance (NEB) early post partum. Typically, NEB is associated with biochemical changes such as high non-esterified fatty acid (NEFA), high β-hydroxybutyrate (β-OHB) and low glucose concentrations. The concentrations of these and other metabolites in the follicular fluid (FF) of high-yielding dairy cows during NEB were determined and extensively analyzed, and then were replicated in in vitro maturation models to investigate their effect on oocyte quality. The results showed that typical metabolic changes during NEB are well reflected in the FF of the dominant follicle. However, the oocyte seems to be relatively isolated from extremely elevated NEFA or very low glucose concentrations in the blood. Nevertheless, the in vitro maturation models revealed that NEB-associated high NEFA and low glucose levels in the FF are indeed toxic to the oocyte, resulting in deficient oocyte maturation and developmental competence. Induced apoptosis and necrosis in the cumulus cells was particularly obvious. Furthermore, maturation in saturated free fatty acid-rich media had a carry-over effect on embryo quality, leading to reduced cryotolerance of day 7 embryos. Only β-OHB showed an additive toxic effect in moderately hypoglycemic maturation conditions. These in vitro maturation models, based on in vivo observations, suggest that a period of NEB may hamper the fertility of high-yielding dairy cows through increased NEFA and decreased glucose concentrations in the FF directly affecting oocyte quality. In addition to oocyte quality, these results also demonstrate that embryo quality is reduced following an NEB episode. This important observation may be linked to the typical diet provided to stimulate milk yield, or to physiological adaptations sustaining the high milk production. Research into this phenomenon is ongoing.
Increased genetic selection over the past 40 years has resulted in a dairy cow with an improved biological efficiency for producing milk but with an associated reduced fertility. Embryo loss is the greatest factor contributing to the failure of a cow to conceive. The extent and timing of embryo loss indicates that 70% to 80% of this loss occurs in the first 2 weeks after artificial insemination (AI). This is the period when a number of critical phases in embryo development occur and where protein accretion, substrate utilization and embryo metabolism increase dramatically. During this time the early embryo is completely dependent on the oviduct and uterine environment for its survival and it is likely that the embryo requires an optimal uterine environment to ensure normal growth and viability. There is increasing evidence of an association between the concentration of systemic progesterone and early embryo loss and that progesterone supplementation of cows, particularly those with low progesterone, can reduce this loss. While progesterone is known to affect uterine function and embryo growth, little is known about the uterus during the period of early embryo loss and how this is affected by changes in the concentration of systemic progesterone. The expression of uterine genes encoding the transport protein retinol binding protein (RBP) and the gene for folate binding protein (FBP) appear to be sensitive to changes in systemic progesterone, particularly during the early luteal phase of the cycle. Uterine concentrations of proteins also seem to be regulated by stage of cycle; however, their relationship with the systemic concentration of progesterone is unclear. There is an urgent need to characterize the uterine environment from a functional perspective during the early part of the luteal phase of the cycle, particularly in the high-producing cow, in order to understand the factors contributing to early embryo loss and in order to devise strategies to minimize or reduce this loss.
Free range pigs, born outdoors and reared after weaning in enriched indoor accommodation, were compared with conventionally raised pigs from a farm, matched for effects on meat quality, with respect to behaviour during transport and lairage, blood chemistry at slaughter and meat quality characteristics. Pigs were either kept in farm pen groups or were mixed at loading and kept in the groups, so formed, until slaughter. Free range pigs tended to settle faster during the 2½ h transport and 2 h lairage than conventionally raised pigs and were more likely to lie as resting posture during transport. Mixing at loading had no effect on posture during transport or during lairage for free range pigs but mixed conventionally raised pigs showed a greater variability in posture during lairage compared to non-mixed conventionally raised pigs, presumably as a result of disturbance from fighting conspecifics. Conventionally raised and free range pigs showed similar levels of aggression during transport but conventionally raised pigs were more aggressive during the lairage (average for mixed groups 12 v. 2 fights, P < 0.001). Aggressive interactions, such as one-way bites, were almost exclusively confined to mixed groups and all fights with mutual biting in mixed groups occurred solely between unfamiliar animals. The frequency of unacceptable skin damage in the middle and shoulder was highest in conventionally raised pigs and in mixed groups. Cortisol concentration and creatine kinase (CK) activity in slaughter blood were not affected by the rearing system. Mixing did not affect cortisol concentrations but led to higher CK activities compared to non-mixing (957 v. 588 U/l, respectively, P < 0.05). The rate of pH fall after slaughter was not affected by the rearing system but muscle temperatures early post mortem were highest in free range pigs. Mixing did not affect pH or temperature early post mortem. Neither rearing system nor mixing at loading affected ultimate pH or internal reflectance (meat quality marbling values).
Following parturition, contamination of the uterine lumen by bacteria is ubiquitous, and uterine health is impaired in cattle because infection persists in 10% to 15% of animals as endometritis. Endometritis causes infertility for the duration of infection, and subfertility persists even after apparent successful resolution of the disease. Escherichia coli is the pathogenic bacterium most frequently isolated from the post partum uterus, and is associated with increased concentrations of peripheral plasma acute phase proteins and fetid vaginal mucus. The presence of E. coli is also associated with slower growth of the first post partum dominant follicle and perturbed oestradiol secretion. Furthermore, in animals that ovulate the first dominant follicle, the corpus luteum is smaller and secretes less progesterone. The endotoxin lipopolysaccharide (LPS), which is released from E.coli, can pass from the uterine lumen to the peripheral circulation and LPS concentrations are increased in cows with uterine infection. Infusion of E. coli LPS into the uterine lumen suppresses the pre-ovulatory luteinising hormone surge and disrupts ovulation in heifers. In vitro, endometrial explants produce prostaglandins in response to LPS. Addition of LPS or E. coli to stromal or epithelial cells increases cyclooxygenase-2 mRNA expression, and stimulates the production of prostaglandin E2 and prostaglandin F2α . Furthermore, uterine and ovarian cells express mRNA of the molecules required for recognition of LPS, Toll-like receptor-4 and CD14. In summary, E. coli is a common cause of infertility involving the perturbation of the hypothalamus, pituitary and ovary in dairy cows.
Sire breed comparisons for carcase (n = 1169), meat and eating quality (n = 686) traits were obtained using data recorded on progeny of known pedigree sired by Duroc (DU), Large White (LW), Landrace (LR) and Duroc Synthetic (DS) boars from crossbred (LW/LR) sows. Animals were reared in eco-shelters in large single-sex contemporary groups and slaughtered on an age constant basis at 22 weeks of age. Compared to progeny from other sire groups, animals sired by purebred Duroc boars tended to have improved eating quality traits (higher intramuscular fat and lower shear force) at the expense of poorer carcase characteristics (higher subcutaneous and belly fat). Animals sired by DS boars tended to be heavier and leaner than those sired by LW, LR or DU boars; intramuscular fat but not belly fat was correspondingly lower, while tenderness was generally consistent with that of the DU progeny. Significant variability of sire progeny groups within sire breed suggests that sire breed selection, potentially used for improving traits such as meat quality in commercial progeny, will be less accurate in the absence of sire-specific information, which is typically poorly recorded in this class of traits.
In order to contribute to the improvement of the national greenhouse gas emission inventory, this work aimed at estimating a country-specific enteric methane (CH4) emission factor for the Italian Mediterranean buffalo. For this purpose, national agriculture statistics, and information on animal production and farming conditions were analysed, and the emission factor was estimated using the Tier 2 model of the Intergovernmental Panel on Climate Change. Country-specific CH4 emission factors for buffalo cows (630 kg body weight, BW) and other buffalo (313 kg BW) categories were estimated for the period 1990–2004. In 2004, the estimated enteric CH4 emission factor for the buffalo cows was 73 kg/head per year, whereas that for other buffalo categories it was 56 kg/head per year. Research in order to determine specific CH4 conversion rates at the predominant production system is suggested.
Belly traits including predicted fat percentage of the belly (FATPC), combined area of the rib bone and muscle (RBMA), intermuscular fat area (IMFA) and subcutaneous fat area (SFA) were recorded on 2403 pigs along with carcase fat depth at the P2 site (P2). Belly traits were derived from image analysis of the anterior side of pork bellies. Further data available for pigs with belly data and their contemporaries included lifetime growth rate, ultrasound backfat and loin muscle depth (35 406 records), along with meat quality traits (3935 records). There were 4586 feed intake records and 18 398 juvenile insulin-like growth factor-I (IGF-I) records available, which included the majority of pigs with belly data. Genetic parameters were estimated based on an animal model using Residual Maximum Likelihood procedures. Heritability estimates for belly traits ranged from 0.23 to 0.34 (±0.05 to 0.06) while the common litter effect varied from 0.04 to 0.07 (±0.03). Genetic correlations between FATPC, individual belly fat measurements and carcase P2 fat depth differed significantly from unity, ranging from 0.71 to 0.85 (±0.05 to 0.08). Genetic correlations between IMFA and subcutaneous fat measurements varied from 0.47 to 0.63 (±0.08 to 0.13). Genetic correlations between belly and performance traits show that selection for reduced juvenile-IGF-I, reduced feed intake and reduced backfat along with increased loin muscle depth will reduce overall fat levels in the belly. Only loin muscle depth had a significant genetic correlation with RBMA (0.32 ± 0.10), thereby assisting selection for improved lean meat content of the belly. Ultimately, genetic improvement of belly muscles requires specific measurements of lean meat content of the belly. For this to be effective, measurements are required that can be routinely recorded on the slaughter line, or preferably on the live animal.
Mutations in the RNA interference (RNAi) genes aubergine (aub), homeless and piwi were tested for effects on the frequency, distribution and coincidence of meiotic crossovers in the long arm of the X chromosome. Some increases in crossover frequency were seen in these tests, but they may have been due to a maternal effect of the balancer chromosomes that were used to maintain the RNAi mutations in stocks rather than to the RNAi mutations themselves. These same balancers produced strong zygotic interchromosomal effects when tested separately. Mutations in aub and piwi did not affect the frequency of crossing over in the centric heterochromatin of chromosome II; nor did a balancer chromosome III.
Previously we performed a 1012-generation mutation accumulation (MA) study in yeast and found that a surprisingly large proportion of fitness-altering mutations were beneficial. To verify this result and assess the impact of sampling error in our previous study, we have continued the MA experiment for an additional 1050 cell generations and re-estimated mutation parameters. After correcting for biases due to selection, we estimate that 13% of the mutations accumulated during this study are beneficial. We conclude that the high proportions of beneficial mutations observed in this and our previous study cannot be explained by sampling error. We also estimate the genome-wide mutation rate to be 13·7×10−5 mutations per haploid genome per cell generation and the absolute value of the average heterozygous effect of a mutation to be 7·3%.
Total body fat mass (TBFM) and total body lean mass (TBLM) are the major components of the human body. Although these highly correlated phenotypic traits are frequently used to characterize obesity, the specific shared genetic factors that influence both traits remain largely unknown. Our study was aimed at identifying common quantitative trait loci (QTLs) contributing to both TBFM and TBLM. We performed a whole genome-linkage scan study in a large sample of 3255 subjects from 420 Caucasian pedigrees. Bivariate linkage analysis was carried out in both the entire sample and gender-specific subsamples. Several potentially important genomic regions that may harbour QTLs important for TBFM and TBLM were identified. For example, 20p12-11 achieved a LOD score of 2·04 in the entire sample and, in the male subsample, two genomic regions, 20p12 (LOD=2·08) and 3p26-25 (LOD=1·92), showed suggestive linkage. In addition, two-point linkage analyses for chromosome X showed suggestive linkages on Xp22 in the entire sample (LOD=2·14) and significant linkage on Xp22 in the female subsample (LOD=3·05). Complete pleiotropy was suggested for 20p12 and 3p26-25 in males. Our results suggest that QTLs on chromosomes 20p12, 3p26-25 and Xp22 may jointly influence TBFM and TBLM. Further fine mapping and gene identification studies for these pleiotropic effects are needed.
In the Brassicaceae plant family, which includes the Arabidopsis and Brassica genera, self-incompatibility (SI) is controlled by genes at the S locus. Using experimental crosses, we studied the pattern of inheritance of S-locus alleles in the wild species Brassica cretica. Four full-sib families were established and unequal segregation of alleles at the SRK SI gene was found in one family. The segregation distortion acted in favour of a recessive (class II) allele and was best explained by some form of gametic-level selection. Our findings are discussed in the light of theoretical predictions of differential accumulation of deleterious mutations among S-locus alleles.
Twin studies have been used to understand the sources of genetic and environmental variation in body height, body weight and other common human quantitative traits. However, it is rather unclear whether these two sources of variation could be really separated in practice. Here, we consider a special study design where phenotype data from married couples and their siblings have been collected. The marital status gives information about the shared environment, while siblings give information about both genetic and environmental variation. To dissect sources of variation and to allow some deviations and pedigree errors in the data, we model such data using a robust polygenic model with finite genome length assumption. As a summary, we provide the estimates for age-dependent proportions of total variation which are due to polygenic and environmental effects. Here, these estimates are provided for body height, weight, systolic blood pressure and total serum cholesterol measured from subjects of the Indian Migration Study.
The hobo-related sequences (hRSs) were considered as degenerate and inactive elements until recently, when one mobilizable copy was described. Using this sequence as the initial seed to search for homologous sequences in 12 available Drosophila genomes, in addition to searching for these sequences by PCR and Southern blot in nine other species, we found homologous sequences in every species of the Drosophila melanogaster species subgroup. Some evidence suggests that these non-autonomous sequences were kept mobilizable for at least 0·4 million years. Also, some very short sequences with miniature inverted-repeat transposable element (MITE) characteristics were found among these hRSs. These hRSs and their ‘MITE-like’ counterparts could provide a good example of the steps proposed in models that describe the MITEs origin.
Osteopontin, a glycoprotein, is expressed in several tissues including the mammary gland. The gene has been reported to be associated with milk and its constituents in various livestock species. This gene was sequenced in buffalo and it coded for the protein of 280 amino acids with the conserved GRGDS domain. The sequence was confirmed from the cDNA sequence derived from the mammary gland of buffalo. The earlier-reported 9T/10T variation in the upstream region of the gene was investigated for its effect on milk in buffalo and it was found to be non-significant.